Question: CDA as a canonical data model

Jun 4, 2014

Question:

I am a university Master student. My thesis involves an implementation of an ESB(Mule) with the CDA R2 schema as a canonical data model (CDM). All of this is done from scratch and I encountered a difficult learning curve but managed to make two target systems interoperable. The systems don’t use the CDA internally so the use of the CDA is just done in the integration solution (ESB).

In my solution I construct a CDA that has a structured body with  sections, lists and elements. The sections dont have codes. Would that make it a level one CDA?

I found the CDA to be very difficult and complex. What are the main problems with the CDA in your opinion? Would it be better to use FHIR instead of CDA?

Answer:

Presumably by “lists” and “elements” you mean lists in the narrative section, and entries with clinical statements? That would make it a level 3 document. At the very least, multiple sections is level 2. (Though there’s some argument about whether you can be level anything without well described templates, and well described templates are not that useful in your case).

You would have found CDA to be very difficult and complex; it’s a clinical document, intended to be used for where “documents” are exchanged between clinicians. For example, referrals, discharge summaries, etc. As such, it was intended to be a “document” with supporting data. That’s not really a suitable thing to use as a “Canonical Data Model” - and so I don’t doubt that you struggled with too much complexity.

CDA does have some issues - see, for instance, my conclusions from the Australian National Program, but the biggest problem is that for all it’s issues, it’s still the accepted way to exchange clinical information, even when this means uses well outside it’s original intention.

Is FHIR better? Yes, I think it will be. It’s natively positioned to be used as a CDM for exchange between clinical systems. It’s based on a much simpler technical base, that ruthlessly targets implementation simplicity. But FHIR is still very much in beta (DSTU = Draft Standard undergoing Trial Use) and so CDA remains the default choice for now.